Nasofarynx

The nasopharynx is the upper portion of the pharynx, located behind the nasal cavities and above the soft palate. It extends from the posterior nares (choanae) to the thin mucous membrane of the soft palate and serves as an airway segment and a conduit for middle-ear drainage.

Key anatomical features include the pharyngeal tonsil (adenoids) on the roof and posterior wall, the openings of the pharyngotympanic (Eustachian) tubes on the lateral walls, and the surrounding torus tubarius. The mucosa is lined by pseudostratified ciliated columnar epithelium with goblet cells, and the submucosa contains seromucinous glands.

Blood supply arises mainly from branches of the maxillary artery and the ascending pharyngeal artery, with venous drainage to the pterygoid venous plexus and nearby veins. Innervation for sensation comes from the pharyngeal branches of the maxillary nerve (V2) via the pharyngeal plexus; parasympathetic and secretomotor fibers reach the mucosa through the greater petrosal and deep petrosal nerves to the pterygopalatine ganglion. Motor innervation to the pharyngeal muscles is via the vagus nerve (via the pharyngeal plexus). Lymphatic drainage primarily targets retropharyngeal and upper deep cervical nodes.

Functions of the nasopharynx include passage of air from the nasal cavity, warming and humidifying inhaled air, and equalization of middle-ear pressure through the Eustachian tubes. Clinically, adenoids can hypertrophy in children, causing nasal obstruction and otitis media with effusion; nasopharyngeal carcinoma is a malignant condition arising in this region, with symptoms such as nasal obstruction, epistaxis, and cervical lymphadenopathy.